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Search: id:A109671
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| A109671 |
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Numbers n > 1 written "as is" if prime or as a concatenation of the prime divisors of n if n is composite. |
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+0
1
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| 2, 3, 22, 5, 23, 7, 222, 33, 25, 11, 223, 13, 27, 35, 2222, 17, 233, 19, 225, 37, 211
(list; graph; listen)
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OFFSET
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2,1
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FORMULA
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a(n)=A037276(n), n>1. [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Aug 18 2008]
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EXAMPLE
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If n=2^3*5^5*11^2 = 3025000, n is written 222555551111 ( n=2*2*2*5*5*5*5*5*11*11, then just remove the stars).
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CROSSREFS
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Sequence in context: A080670 A073647 A073646 this_sequence A037276 A068190 A084796
Adjacent sequences: A109668 A109669 A109670 this_sequence A109672 A109673 A109674
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KEYWORD
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easy,nonn
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AUTHOR
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Pierre CAMI (pierrecami(AT)tele2.fr), Aug 06 2005
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